A former deputy mayor of Chechnya's capital, Grozny, has been shot dead in western Moscow - the third killing of a high-profile Chechen since September.
Gilani Shepiyev was shot three times in the head by a gunman outside his flat in a suspected contract killing.
He had fled Grozny in 2006 after being injured in an assassination attempt.
An opponent of Chechen President Ramzan Kadyrov was shot dead in Moscow in September. Last month, one of his former bodyguards was killed in Vienna.
Mr Kadyrov has denied any involvement.
A spokesman for the investigations committee of the Russian Prosecutor-General's Office, Vladimir Markin, said Mr Shepiyev's body was discovered close to the entrance of his flat in Moscow early on Thursday morning.
Mr Kadyrov has strenuously denied involvement in the two earlier deaths
The crime scene and the victim's body were being examined by police investigators, he added. A Baykal pistol was found nearby.
"The investigation believes that it was a contract killing. All possible theories are being considered," Mr Markin told Russian Vesti TV.
Mr Shepiyev was Grozny's deputy mayor from 2004 to 2006. Russian media reported that he supervised law enforcement agencies in the southern republic.
He moved to Moscow in 2006 after escaping an attempt on his life.
Thursday's killing is the third of a prominent Chechen since September, when Ruslan Yamadayev, a member of a prominent family which opposed President Kadyrov, was shot dead as his car stood at traffic lights in central Moscow.
On 13 January, Umar Israilov, a former bodyguard for the Russian-backed leader who had accused him of torture and kidnapping, was shot dead on a street in Vienna.
Later that month, Stanislav Markelov, a top human rights lawyer who acted for the family of a Chechen woman murdered by a Russian army officer, was shot dead in central Moscow along with a journalist, Anastasia Baburova.
Chechnya has been devastated by heavy fighting since 1994, when Russian troops first poured in to crush a separatist movement.